Extraction-spectrophotometric determination of germanium with phenylfluorone in N,N-dimethylformamide

Abstract

Germanium(IV) is extracted as GeCl₄ into toluene from 9.5 M HCI solution. The spectrophotometric determination of Ge is carried out in the same extracted phase by the addition of phenylfluorone (PF) solution in N,N-dimethylformamide. The Ge(IV)-PF complex gives an absorption maximum at 525 nm with a molar absorptivity of 7.08 ± 0.02 × 10⁴ l mol^–1 cm^–1. This procedure compares favourably with respect to selectivity and stability with other methods for the determination of germanium using PF. The method has been applied to the determination of germanium in lignite ashes with good precision and accuracy. The results obtained by this method are compared with those obtained by two AAS methods (extraction of GeCl₄ into hexane with flame AAS and also hydride generation).